/* 
  自适应屏幕尺寸
 */
const buildRem = function () {
  let designSize = 1920; // 设计图尺寸            
  let html = document.documentElement;
  let wW = html.clientWidth;// 窗口宽度
  let rem = wW * 100 / designSize;
  html.style.fontSize = rem + 'px';
}
// 页面初始化的时候调用
buildRem()
// 页面缩放时调用
window.onresize = buildRem;
